Go1.18: runtime: goroutine stack exceeds 1000000000-byte limit with generic function

[nikgalushko]

What version of Go are you using (go version)?

$ go version
go version go1.18beta1 darwin/amd64

Does this issue reproduce with the latest release?

No.

What operating system and processor architecture are you using (go env)?

go env Output

$ go env
GO111MODULE=""
GOARCH="amd64"
GOBIN="/Users/nikita.galushko/go/bin"
GOCACHE="/Users/nikita.galushko/Library/Caches/go-build"
GOENV="/Users/nikita.galushko/Library/Application Support/go/env"
GOEXE=""
GOEXPERIMENT=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GOINSECURE=""
GOMODCACHE="/Users/nikita.galushko/go/pkg/mod"
GONOPROXY=""
GONOSUMDB="stash.lamoda.*"
GOOS="darwin"
GOPATH="/Users/nikita.galushko/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/local/go"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/local/go/pkg/tool/darwin_amd64"
GOVCS=""
GOVERSION="go1.18beta1"
GCCGO="gccgo"
GOAMD64="v1"
AR="ar"
CC="clang"
CXX="clang++"
CGO_ENABLED="1"
GOMOD="/Users/nikita.galushko/Documents/GitHub/fx/go.mod"
GOWORK=""
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -arch x86_64 -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/var/folders/qw/1tqq14qj6zl92hzqm3mk0vdwzh7_yw/T/go-build3942344120=/tmp/go-build -gno-record-gcc-switches -fno-common"

What did you do?

I'm trying Golang generics and catch a strange behavior: stack overflow with simple code. If I write the same code with a specific type, it will work as expected. You can check it on playground.
The minimal code is:

func test[A ~[]T, T comparable](arr ...A) A {
	var ret A

	switch len(arr) {
	case 0, 1, 2:
		return ret
	default:
		return test(arr[2:]...)
	}
}

What did you expect to see?

no fatal error

What did you see instead?

runtime: goroutine stack exceeds 1000000000-byte limit
runtime: sp=0xc020460468 stack=[0xc020460000, 0xc040460000]
fatal error: stack overflow

runtime stack:
runtime.throw({0xd21d63?, 0x12eb300?})
	/usr/local/go/src/runtime/panic.go:992 +0x71
runtime.newstack()
	/usr/local/go/src/runtime/stack.go:1101 +0x5cc
runtime.morestack()
	/usr/local/go/src/runtime/asm_amd64.s:547 +0x8b

goroutine 1 [running]:
cmd/compile/internal/types2.(*unifier).nify(0xc00016e630, {0xe8e7c0?, 0xc0003cfcb0?}, {0xe8e748?, 0xc00002d130?}, 0x0)
	/usr/local/go/src/cmd/compile/internal/types2/unify.go:239 +0x11c5 fp=0xc020460478 sp=0xc020460470 pc=0xba1505
cmd/compile/internal/types2.(*unifier).nifyEq(0x0?, {0xe8e7c0?, 0xc0003cfcb0?}, {0xe8e748?, 0xc00002d130?}, 0x0?)
	/usr/local/go/src/cmd/compile/internal/types2/unify.go:232 +0x96 fp=0xc0204604d8 sp=0xc020460478 pc=0xba02d6
cmd/compile/internal/types2.(*unifier).nify(0xc00016e630, {0xe8e7c0?, 0xc0003cfcb0?}, {0xe8e748?, 0xc00002d130?}, 0x0)
	/usr/local/go/src/cmd/compile/internal/types2/unify.go:266 +0x314 fp=0xc020460678 sp=0xc0204604d8 pc=0xba0654
cmd/compile/internal/types2.(*unifier).nifyEq(0x0?, {0xe8e7c0?, 0xc0003cfcb0?}, {0xe8e748?, 0xc00002d130?}, 0x0?)
	/usr/local/go/src/cmd/compile/internal/types2/unify.go:232 +0x96 fp=0xc0204606d8 sp=0xc020460678 pc=0xba02d6
cmd/compile/internal/types2.(*unifier).nify(0xc00016e630, {0xe8e7c0?, 0xc0003cfcb0?}, {0xe8e748?, 0xc00002d130?}, 0x0)
	/usr/local/go/src/cmd/compile/internal/types2/unify.go:266 +0x314 fp=0xc020460878 sp=0xc0204606d8 pc=0xba0654
...additional frames elided...

Go build failed.
About the Playground

The Go Playground is a web service that runs on go.dev's servers. The service receives a Go program, vets, compiles, links, and runs the program inside a sandbox, then returns the output.

[seankhliao]

Duplicate of #48619